It is well known that hardness, microorganisms and suspended solids in water sources vary widely in composition depending on the source and will result in scale deposition including microbial tuberculation and sedimentation on surfaces wherever water is used. Scale deposition and sedimentation is particularly troublesome in water distribution pipe systems which service the residential and commercial customers of municipalities, private water companies and the like along with industrial process water distribution pipe systems as found in the mining, petroleum, agriculture and the like industries. In these systems, the formation of scale, tuberculation and sediment can reduce the water flow through the pipe system which will limit the capacity of the pipe to service the requirements of the customers or to provide the required water necessary for an industrial process, irrigation, etc. For instance, in municipal systems an increase in the fire risk would be obvious if the fire hydrant did not supply sufficient water to extinguish the fire due to scale, tuberculation and sediment deposits in the feed pipe line. At some point, the water distribution pipe would have to be replaced due to these restrictions at a high cost and with prolonged interruption of service.
Additionally, scale, tuberculation and sedimentation will increase the possibility of corrosion in the water distribution pipe along with promoting the growth of other organisms. The organisms also can be a health hazard, promoting corrosion and biomass which binds scale and sediment together and to the surfaces of the system. Corrosion can eventually lead to the leakage of the system and the necessity to replace the leaking section.
The microbiological tuberculation found in water distribution pipes and wells are typically due to iron and manganese bacteria that attach themselves to the walls of the pipe and live on the soluble iron or manganese in the water along with other nutrients. Their spaghetti-like features also allow them to trap all particulate matter which is present in the water.
There are over 20 different iron bacteria that have been characterized. As part of their metabolism, they convert ferrous ion to ferric ion which results in iron oxide (rust) accumulation in the tuberculation. Manganese bacteria convert manganous ion to manganic ion which results in manganese dioxide accumulation in the tuberculation in the water pipe. After generations of bacteria, the iron oxide, manganese dioxide, particulate matter and biomass accumulation on the side of the pipe results in mounds of tuberculated "growth" annalogous to a coral reef.
As the tuberculation grows, flow becomes increasingly restricted and turbulant. This leads to red water and turbidity complaints by consumers. Restricted flow results in low pressure complaints and poor hydrant performance. Tuberculation can also interfere with valve and hydrant performance and operation. There can also be corrosive sulfate reducing bacteria that live under the tuberculation and cause pipe corrosion.
Strong acids have been used to clean water wells, however, submersible pumps are removed prior to treatment to prevent corrosion by the acids employed. Also, organic acids, mixtures of mineral acids and organic acids or inhibited acid compositions have been found to clean water wells without the necessity of removing the pumps or other equipment. These methods for cleaning water wells have involved static and surging treatment.
A proper cleaning and maintenance program for water distribution systems will prevent decreased water flow capacity, corrosion and the necessity to replace the system or portions thereof. A simple and effective method for cleaning and maintaining these systems is needed.